Improvement in adjusting devices for weighing-scales



F FAIRBANKS Adjusting Device for Weighing-Scales.

Patented 090.18, 1877.

SK A.

N. PETHZS, PHOTO LTHOGRAP UNITED STATES PATENT OFFICE.

FRANKLIN FAIRBANKS, OF ST. J OHNSBURY, VERMONT.

IMPROVEMENT IN ADJUSTING DEVICES FOR WElGHlNG-SCALES.

Specification forming part of Letters Patent No. 198,366, dated December18,1877 application filed September 28, 1877.

To all whom it may concern:

Be it known that I, FRANKLIN FAIRBANKS, of St. J ohnsbury, Caledoniacounty, in the State of Vermont, h ve invented certain new and usefulImprovements relating to Equal- Beam Scales, of which the following is aspecification.

The object of the invention is to better'provide for delicatelyadjusting the balance.

It is common to make the beam of cast-iron, with an opening in thecenter. I increase the capacity of the opening, and mount a screwtherein at the level of the knife-edges, and a balanced pawl or weightis threaded upon this screw, and may be turned to any required de greeto cause it to shift its position gradually toward one end or the otherof the beam.

I crook the screw rod and peculiarly mount it, in order that the centerof gravity of the balance-pawl be down at or near the level of theknife-edges, and also to cause the balanceball and its supporting-screwto be more effectually out of the way and protected from danger ofaccidental blows, and the like, and to facilitate the introduction andremoval of the parts. The main part of the rod is straight andscrew-threaded, and adapted to be inserted at one end into a horizontalhole at the end of the cavity at the mid-height of the lever. The otherend is crooked, being bent quite sharply upward till it reaches thelevel of the top of the lever, and then extended horizontally again.Through this last horizontal extension is inserted a screw, whichsecuresthe whole.

The accompanying drawings form a part of this specification, andrepresent what I consider the best means of carrying out the invention.

Figure 1 is a side elevation, partly in section. Fig. 2 is a plan view.

Similar letters of reference indicate like parts in both the figures.

Ais the frame-work; B, the beam, supported on knife-edges at the center,as usual, and supporting the pans or disks 0 on knifeedges equidistantfrom the central support, while 0 c are the stems or upright parts,connected to the disks 0, and D D are the bottom links, arranged toserve as usual.

The beam B has a capacious cavity between the supporting knife-edges atits center. A horizontal hole or step is formed at one end of thiscavity, which receives the end of a finely-threaded screw, 0, whichcarries a correspondingly-threaded pawl or weight, E. The other end ofthe rod E has an oifset, extended squarely upward, and thence extendedagain horizontally, as indicated. A screwfastening, e, is insertedthrough the hole in the flattened end of the rod 6, which is, by meansof the offset shown, caused to lie upon the upper face of the beam.lVhen, from any irregular wear or other cause, the scales become out ofbalance, the turning or partial turning of the ball E causes it tochange its position longitudinally on its threaded support and restorethe equilibrium.

The rod 0, formed as described, supports the ball E at such a level thatit has no elfect in disturbing the sensitiveness of the scale, as itwould if above or below the line of the knife-edges. Furthermore, thecarrying the ball in this manner in the cavity in the beam holds itbetter protected than it would otherwise be against danger of receivingshocks and injuries in moving or operating the scale.

The difficulties attending the proper mounting of a balance-ball on thisclass of scale are successfully overcome by this invention, and thescales may be balanced and readily adjusted with ease and with anyrequired degree of nicety.

I claim as my invention- The screw-rod e, bent as shown, in combinationwith the fastening-screw e, balance-ball E, and with the beam B of anequal-beam scale, adapted to serve as and for the purposes hereinspecified.

In testimony whereof I have hereunto set my name in presence of twosubscribing witnesses.

FRANKLIN FAIRBANKS.

Witnesses:

E. D. BLODGETT, D. DEAN PATTERSON.

